Scottish Labour, however, are facing a devastating election with
leader Jim Murphy set to lose his seat after an Ipsos Mori poll
showed the SNP could win in every Scottish constituency.

Farage has pledged to quit as UKIP leader if he loses the battle
for South Thanet to Conservative candidate and previous MP Craig
Mackinlay.

Other pollsters Ipsos Mori, which two weeks ago gave Labour a
lead of two percentage points, showed on Thursday the Tories are
leading by five points and are predicted to be the largest party
after polling day.

The polls have consistently shown a very small margin between the
two biggest parties, but in recent weeks the trend has suggested
a miniscule lead for Labour.

Despite suggestions the Conservatives will hold the most seats,
figures still predict Ed Miliband will hold the balance of power
when it comes to forming a government.

It remains unlikely any of the parties will win enough seats to
form a single party majority government. Miliband and Cameron
will need to court the support of smaller parties to be able to
control the House of Commons.

Four smaller parties – the SNP, Plaid Cymru, the Greens and the
DSLP – have already said they would vote against a Tory
government. Analysis by the Guardian suggests that combined with
Labour, the total bloc of 331 seats would be enough to rule out
Cameron.